Automatic grinding machine



Feb. 9, 1937. A, 1 LEWIS i 2,070,283'

AUTOMATIC GRINDING' MACHINE Filed Dec. e, 1952' '7 sneetsl-sheef 1 ATTORNEYS Feb. 9,1937. A. J. LEwls AUTOMATIC GRINDING MACHINE Filed Dec. 6, 1932 7 Sheets-Sheet 2 m m Mm V Feb. 9, 1937. l A. J, LEWIS 2,070,283

AUTOMATIC GRINDING MACHINE Filed Dec. 6, 1952 7 Sheets-Sheet 3 Feb. 9, 1937, A, J. Li-:wls

AUTOMATIC GRINDING MACHINE Filed Deo. 6, 1932 7 Sheets-Sheet 4 INVENTOR l a' ATTORNEYS Feb. 9, 1937. A. J. LEWIS AUTOMATIC GRINDING MACHINE 7 sheets-sheet 5 Filed Deo. 6, 1952 INVENTOR ,XX l

@drn/Q ATTORNEYS Feb. 9, 1937. A. J. I Ewls 2,070,283

AUTOMATI C GRINDING MACHINE Filed Dec. 6, 1932 '7 Sheets-Sheet 6 XM; n /21/ /67 l N ving/2] yf Feb. 9, 1937. A. J. I Ewls AUTOMATIC GRINDING MACHINE INVENTOR ATTORNEYS Patented Feb. 9, 1937 UNITED STATES PATENT OFFICE The Baird Machine Company,

Bridgeport,

Conn., a corporation of Connecticut Application December 6, 1932, Serial No. 645,913

42 Claims.

This invention relates to grinding machines, and has particular reference to multiple spindle grinding machines in which a plurality of grinding tools operate simultaneously upon acorrespending number of pieces of work.

In the machine of the invention, the pieces of work are secured in proper position in a plurality of work holders arranged in circular series in a turret, which indexes after each tooling operation relatively to a tool carriage having a circular series of grinding tools which act successively vupon each piece of work, each tool performing part of a single machining operation upon each piece of work. This arrangement permits all of the tooling steps which are necessary to complete the grinding of each piece of work to be performed in a single machine, so that the work emerges in finished form without requiring further grinding. 20 The tool holders on the tool carriage are substantially axially aligned with the work holders when the turret is stationary, and are traversible relatively to the turret and the tool carriage to engage the tools with the work for the tooling operation and then return to inoperative position in readiness for the next tooling operation on successive pieces of Work presented by the indexing action of the turret.

The tool carriage is reeiprocated axially relatively to the turret toradvance and retract the tools to and from the plane of the work in which the tooling operation takes place. These reciproeating movements of the tool carriage alternate with the traversing movements of the tool holders, so that the tools describe a rectangular path between their periodic tooling operations.

superimposed upon this major reciprocating movement of the to-ol carriage, during the period that the tools are acting upon the work, is a rapid reciprocating movement of small amplitude, so that each tool, as it grinds, wipes across the surface of the corresponding piece of work to cause the minute scoring marks made by the tool to er traversing mechanism, which supermposes upon the major traversing movement of the tool holders a small advancing movement equal to the amount which the radius of each individual tool was reduced, so that the tools perform a uniform 5 grinding operation in each successive piece of work. A safety device is associated with this compensating mechanism which automatically disables it when one or more of the ltools is worn and dressed down to the core or to the point where it m is no longer effective or would injure the work, so that the tool does not materially engage the work during the following working cycle, if the operator neglects to replace it.

The tools are rotated continuously and the Work 15 holders are also rotated continuously in a direction opposite to that of the tools, except during the interval that the work holders are positioned at the loading station after having been advanced one by one to that point by the indexing movements of the turret. At the loading station the rotation of the work holders is automatically suspended to enable the operator to remove the finished pieces of work and replace them with new work. If the operator fails to remove finished work from the work holders which are advanced to the loading station, the entire machine is automatically stopped to prevent regrinding of the finished work..

The progressive grinding of the Work with the machine of the invention permits the use of a series of different tools, each particularly adapted for performing a special step in the complete grinding operation. For example, the first tool of the series may be a roughing tool for dressing down the uneven surface of a casting, forging, or the like, to prepare it for the less coarse roughing cut of the succeeding tool, and so on to the nal tool of the series, which may produce a fine polish or a lap, depending upon requirements. Inv addition to the initial selection of the various tools for producing the several ground eilects, the tools are individually adjustable to produce deep or shallow cuts, the coarse or roughing tools being adjustable to produce a deep cut and the fine grinding tools a ner cut, although each tool invariably follows the fixed square motion path, modified by the rapid oscillation of the tool across the surface of the work and by the adjustment of the tool relatively to the work to compensate for the wear and dress of the tool.

This invariable relationship between the tools andthe work is maintained for all positions of the machine, since all movements of its parts are pomme, Accordingly, the tools and work may be separated at will by retractingthe tool carriage by moans provided lor that purpose to enable the operator to replace worn tools, or thc like. at any stage of the operation, without disturbing the adjustment or relation of any part, so that the tool carriage may be restored to its initral position for resuming the tooling operation at the point where it was interrupted.

While the machine of this invention is particularly adapted for performing grinding operations, its use is not limited to that purpose, since the principles of operation and the timed movements thereof may be incorporated in a machine for performing tooling operations of a different nature. These general principles of operation and timed movements are more completely described in the following description of the preferred embodiment of the invention which is illustrated in the accompanying drawings, in which Figure 1 is a vertical section through the center of the machine, as seen along the line l-l of Fig. 3;

Figure 2 is a front elevation of the machine illustrating, in section, portions of the tool-holder traversing mechanism;

Figure 3 is a plan view of the machine;

Figure 4 is a horizontal section through the base of the machine, as seen along line 4-4 of Fig. l, and illustrates the machine drivi and turret indexing mechanism;

Figure 4A illustrates a substitute turret indexing cam for rendering the machine double-indexlng;

Figure 5 is a vertical section through the gear box of the driving mechanism, as seen along line 5-5 of Fig. 4;

Figure 6 is a vertical section throtgh the driving mechanism, as seen along the line 6-6 of Fig. 4 and particularly illustrates the arrangement of the two-speedshaft thereof;

Figure '1 is an enlarged axial section through the work-holding chuck;

Figure 8 is an enlarged axial section through the work-holding chuck driving mechanism;

Figure 9 is a development of the tool carriage reciprocating cam;

Figure 10 is a horizontal section through the machine as seen along the line |0|0 of Fig. 1, and illustrates the arrangement of the tool dressing devices;

Figure 11 is an enlarged section of one of the tool dressing devices;

Figure 12 is a horizontal section through the tool carriage, as seen along the line |2| 2 of Fig. 1, and illustrates the arrangement of the tool holders;

Figure 13 is an enlarged partial section through the tool carriage and illustrates the structure and arrangement of the tool holders and their operating cams;

Figure 14 is a diagram illustrating the rectangular or square motion path of the tools;

Figure 15 is a top view of a piece of work and the tool cooperating therewith;

Figure 16 is a horizontal section through the base of the machine as seen along line |6|6 of Fig. 1 .and illustrates the safety stop and work release mechanisms;

Figure 17 is an enlarged top view of the tool holder traversing and tool Wear and dress compensating mechanisms;

Figure 18 is a front view thereof;

Figure 19 is a vertical section through the aut0- maticv stop device of the compensating mechanlsrn, as seen along vthellne |9-I9 of Fig. 17;

Figure 20 is a partial side view of the base of the machine showing the work release treadle at the loading station;

Figure 21 is an enlarged view of the safety mechanism which stops the machine if the operator fails to operate the treadle to remove finished work; and

Figure 22 is a partial section through the manual. tool carriage elevating mechanism, as seen along line 22-22 of Fig. 12.

Referring to Fig. 1 of these drawings, numeral 20 designates the base of the machine upon which is supported the column 2| having the lateral extension 2|' and which carries the pedestal 22, which serves as the axis of the machine.

The driving mechanism to clutch release collar 22 vsplined on shaft 2li and operable by a yoke 33 connected to shifter rod 34 slidably mounted in the gear box 21.

Spur gear 3|) meshes with spur'gear 35 journailed on jack shaft 3|; journalled in the gear box 21v (Fig. 4). The spur gear 35 is provided with an extension housing normally engaged disc clutch 31, the other element of which is connected to release collar 38 splined on jack shaft 36 and operable by a yoke 39 mounted on shifter rod 40 slidable in gear box 21 and shiftable by a rod 4| having a crank 42 at one end engaging a collar 43 on rod 40 and actuable in a manner to be described.

The skew gear 29 on drive shaft 23 meshes with a skew gear 44 on cross shaft 45 journalled in gear box 21 and this cross shaft drives a second parallel cross shaft 46 by means of spur gears 41 and 48. Cross shaft 46 is suitably journalled in gear box 21 and carries a worm 49 which meshes with worm wheel 50 journalled on jack shaft 36. 'Ihis worm Wheel 50 is provided with a plurality of spring pressed pawls 5| engaging a ratchet 52 formed integrally with spur gear 35 and driving the latter in a clockwise direction independently of meshing spur gear 30 when clutch 3| is disengaged.

It will be seen that when clutch 31 is engaged, as is the case when the machine is operating normally, jack shaft 36 is driven at a certain speed directly by motor 24 through belt 25, pulley 26, drive shaft 28, skew gears 29 and 44, cross-shaft 45, spur gears 41 and 48, cross-shaft 46, worm 49, worm wheel 50, pawls 5|, ratchet 52, clutch 31, and collar 38 which is splined on jack shaft 36.

It will also be seen that when clutch 3| is engaged, spur gears 30 and 35 are directly driven and that, because of the higher gear ratio, the

shaft 55 journaled at its lower end in a. step bearing 56 in the base 28, and near its center and upper end in the bearings 51 in the base 28 and frame 2|, respectively. This shaft carries a cam disc 58 having several cams, one of which, inside ring cam 58', cooperates periodically with one end of bell crank 68, which is pivoted on the gear box 21 and engagesla collar 6| on the shifter rod 34 of normally disengaged clutch 3|. When cam 59' engages crank 60, the latter shifts rod 34 to the left, as seen in Fig. 4, to engage clutch 3| so that cross-shaft 36 and consequently cam shaft 55 are driven -at a higher speed, ratchet 52 slipping past its pawls 5| in the manner described. Clutch 3| remains engaged until cam 59 engages bell crank 60 to shift rod 34 to the right to disengage clutch 3| so that cam shaft 55 is driven at slower speed through pawls 5| and ratchet 52.

The turret Journaled on bushings 63 on the pedestalI 22 of the machine is the turret 64, which is rotatably supported on a track 65 mounted on the upper surface of base 20. The turret 64 is indexed rapidly during the high speed drive period of the cam shaft 55, and the indexing mechanism includes a pair of spaced roller pawls 66 mounted on cam ring 58 and successively engaging one of the spaced lugs 61 on ring 68 secured on the lower edge of the turret 64. Each indexing movement rapidly rotates the turret one step through a predetermined angle between adjacent tooling stations in a manner readily understood.

The turret 64 is locked against movement during the period between its indexing movements by a pin 69 adapted to engage any one of a plurality of notches or slots 10 in the turret 64. 'I'his pin is slidably mounted in the base 26, is held in place by cap 1| and is normally urged inwardly into one of the notches 1|) by spring 12. The pin 69 is provided with a side slot into which projects the end of a bell crank 13 pivoted on the `ibase 26 and engaging a cam 14 on cam disc 58. This cam 14 actuates lever 'i3 to withdraw pin 69 from the corresponding notch 18 at the beginning of the indexing movement of the turret 64, holds pin 69 disengaged during the indexing movement of the turret and then releases pin 69 for insertion in the next notch 10 after the indexing movement is completed, so as to lock the turret' while the grinding operations take place.

n addition to the locking pin 69, the turret 64 is provided with a friction brake' at the nishing stations on the left hand side of the machine, as seen in Figure 4. This brake comprises a spring shoe 64 engaging the exterior surface of the turret 64 and adjustable to vary its frictionall resistance by means of a set screw 65' mounted on the base 28 (Figures l and 4). 'I'he brake holds the turret 64 rmly against the pedestal 22 so that any looseness is taken up at the finishing stations whereby there can be no variation in the grinding action and absolute accuracy at the finishing stations is secured. The brake also prevents any tendency of the turret to over-run during the indexing movements thereof.

The machine may be readily converted from single indexing, i. e., where each tool cooperates with each successive piece of Work, to double indexing, where the tools skip alternate pieces of work. In other words, instead of moving through the angle between two adjacent tooling stations, the turret moves through a double angle. This conversion is accomplished by substituting for the two-roller cam disc 58 the four-roller cam disc 58 illustrated in Figure 4A, which carries the four rollers 66' arranged to engage two suc.

cessive lugs 61 on ring 68 instead of one lug 81,

'so that the turret is moved through a double The work holders The turret 64 carries the chucks or other work holders, of which there maybe any number consistent with requirements and the size of the machine. In the machine illustrated eight chucks are employed. 'I'he construction, sizeand shape of the chucks depend upon the work to be held therein.. By way of illustration, the work W illustrated in the drawings is an automobile hub, the interior surface of which is to be ground. The chuck for holding such a hub is illustrated in enlarged section in Fig. 7 and comprises a block 15 bolted on the upper end of a tubular sleeve 16 rotatably supported by upper and lower roller bearings 11 in an opening in the turret 64, as shown in Fig. 1. 'I'he joint between the block 15 and the turret 64 is sealed by ring 11 against the Water supplied to the grinding tool, which normally ows from the work W into block 15, through discharge slot 18 therein, and into the gutter 19 in the base 20, which discharges through pipe 89 at the rear of the machine, as shown in Fig. 4. The block 15 is fitted with a cup 8| for receiving the work W, which has a flange provided with openings through which centering pins 82 of the cup pass.

. Slidably mounted within the sleeve 16 and centered therein by bushing 834s a spindle 84, which is normally urged downwardly by spring 85. The spindle 84 is provided with a head 86 having three pivotedv pawls 81, forming with cup 8| a collet chuck in which the work W is gripped. The upper ends of the pawls 81 are urged by the lower f rim of cup 8| into a groove in the work and the 81 from the groove in the work W to release it.

Pawls 81 are normally urged within cup 8| and into engagement with the work W by the spindle spring 85.

Splined on the lower end of chuck sleeve 16 is the male element 89 of a cone clutch, the female element 98 of which is journalled on sleeve 16 and has an integral spur gear 9|, which meshes with a spur gear ring 92 journalled on ball bear,- ings 93 on the pedestal 22 of the machine. The lower edge of gear ring 92 is provided with a bevel gear 94, which meshes with and is constantly driven by bevel gear 95 on the end of shaft 96 journaled in the base 20 of the machine. The shaft 96 is driven directly by drive shaft 28 through bevel gears 91 and 98, as is illustrated in Fig. 4.

Spindle cone clutch 89--90 is normally held in engaged position by a coil spring 99 interposed between male clutch element 89 and a ring |88 mounted in the end of sleeve 16. The work-holding chucks and their spindles are accordingly driven continuously throughout the several grinding operations and are stopped only to enable the operator to remove the finished Work W and reload the chucks. The stopping of the chucks and spindlesat the loading station is performed automatically by a cam-operated release mechanism for the spindle clutches. This mechanism includes a grooved collar in the male clutch element 09, in the grooveof which lie the ends of a forked release lever |02 which is pivoted beof sufficient length to simultaneously accommodate two rollers |00, so that after each indexing movement of the turret ad, two chucks are stationary. During the next indexing movement of turret t0, one of the rollers |02 moves off of the cam |05 and the spring 09 reengages the clutch 804-90 to rotate the corresponding chuck and spindle.

Loading and unloading During the interval that the two chucks remain stationary at the loading station, they 'are automatically opened for Athe release and removal of the finished work W and for reloading with the next piece of work to be ground. The mechanism for opening the chucks includes a. pair of vertical pins |06 which are aligned with the lower ends of the spindles 80 of the two chucks which remain stationary at the loading station between indexing movements of the turret 6|. These pins |06- slide vertically through guide bar |07 mounted on the pedestal 22, and are adjustably threaded in arms |08 pivoted in the forks ofvcranks |09 secured to a shaft ||0 journalled in a bracket H0 on pedestal 22. The left-handend of shaft |0, as seen in Figs. 1 and 16, carries the lever having roller ||2 at its end. 'Ihis roller ||2 engages inverted crown cam I3 keyed on cam shaft 55 and operative to rotate shaft ||0 at the\end of 'each indexing operation so as to cause pins |00 to engage and lift the corresponding spindles 84 of the two stationary chucks located at the loading station at that time. Elevation of spindles 84 causes the detents 08 of the chuck pawls 8l to engage the lower rim of chuck cap 8| and ,swing the ends of pawls 8l out of the groove in the work W to release the latter. The length of crown cam H3 is such that the two chucks at the loading station remain open during the interval between indexing movements of the turret 02 so theoperator has ample time to remove the finished piece of work W from the open chucks and replace them with new pieces of work.

The chuck-controlling shaft ||0 is also provided with vertical lever IM having the roller l5 which engages the ring cam |6 on the under surface of worm gear 50 of cam shaft 55. This ring cam |10 succeeds crown cam i3 in operation and is complementary thereto and serves to positively retract and hold retracted the spindle-engaging pins |06 during the indexing movements of the turret 04| so that there can be no interference between the pins |00 and the chuckspindles 80 when the turret B4 is moving.

During the dwell period of the turret 04 when the two chucks at the loading station are open, the work W may be readily removed from and placed in the chucks. Before the operator can have access to the finished work W presented at the loading station he must withdraw ngers lll,

which lie over the work but out of contact therewith, as shown in Figures 2, 10 and 20. These fingers are mounted on a horizontal shaft H2 pivoted in lugs ||9 ony the apron |20, which is mounted on the base 20 and encloses the chucks, work W, and other working parts of the machine. The left-hand end of shaft H2, as seen in Figures 2, 10 and 20, carries the lever |2|, to the end of which is pivoted one end of rod |22 connected at its lower end to the treadle |23 pivoted on lugs |26 on the base 20 of the machine at the loading station. The fingers ||l are urged downwardly to a position over the work W`by spring |25 and a pin |26 limits this downward movement of the fingers to hold them out of contact with the work.

The operator of the machine is supposed to remove each finished piece of work W from its chuck at the loading station and replace it with a new piece during the dwell period of the turret, and to enable him to do this he depresses treadle |23 to withdraw fingers from the work W. A safety device (Figures 2, 16 and 21) is provided to stop the machine in the event that the operator fails to remove a finished piece of work. This safety device is operative only when the operator fails to depress treadle |23 preparatory to removing the work. The, safety device includes a link |27 connected at one endby a pin-and-slot |20 to treadle rod |22 and at the other end to a bell crank lever |29 which is fixed to shaft |20 journaled through a boss |3| on the base 20. 'Ihe inner end of shaft |30 carries a crank |82 which engages crown cam |32 mounted on the upper surface of worm wheel 50. Pivoted on link |2`| near its center is a rocker plate |35 having `two lateral detents |30 and |32 which are adapted under certain conditions to respectively engage abutments |38 and |39 on plate |20 secured to the base 20. Pivoted on link |2'| is a latch |ll| having a notch forming a hook |22 .at its extreme end which cooperates with a pin |233" on the end of stop handle |03, which is fixed to the end of rod 0|, which, it will be recalled, controls master clutch 3l of the drive mechanism of the machine. 'This clutch is normally engaged and, when disengaged by the rotation of rod 2| stops the machine. A disengage lever |22 is pivoted on link |27 and, when manually thrown toV operative position, lifts latch |li| out of the path of the pin |23' to disable the safety device.

The safety device is so arranged that when the' operator depresses treadle |23 to release the flngers Il and remove the finished work from the two then open and stationary chucks, link |2`| is depressed by treadle rod |22 to lower plate |35 and cause its lower detent |31 to engage abutment |39, While upper detent |36 passes below and clears abutment |38. This action causes plate |35 to rotate about its pivot so that detent |31 engages latch itl to lift the hook |02 of the latter clear of pin |43' on stop handle |23. Immediately thereafter crown cam |30 actuates crank |20 to move link |2'| to the right as seen in Figs. 2 and 21. Since hook |02 of latch |0| has been withdrawn from pin |03 of stop handle |23 by the depression of treadle |23, the hook |22 does not actuatethe handle |03, and the feeler action of crown cam |34 is ineffective. However, if the operator has failed to depress treadle |23 preparatory to removing the finished work from the stationary open chucks, link |2`| remains in raised position and the feeler action of cam |30 moves link |2`| to the right so that detent |30 engages abutment |38 to withdraw detent |3 from latch Mi. Continued movement of the link |21 by the cam 34 causes latch hook |42 to pull pin. |43' to the right to rotate rod 4| and disengage clutch 31 to stop the machine. The machine may be stopped manually at'any time by movement of the handle to the left, as seen in Fig. 2.

The tool carriage The pillar |45 of the machine upon which the tool carriage is mounted is secured upon pedestal 22 by bolts |46 and its upper end is seated in an opening in the column extension 2|', which is covered by cap plate |41. This pillar |45 is provided with an axial bore |48 into which projects the upper end of push rod |49 which is slidably mounted in the pedestal 22. Extending crosswise through opposite elongated vertical slots |50 in the pillar |45 is a cross-bar |50.

Threaded through this cross-bar and engaging 1 the upper surface of push rod4 |49 is adjusting rod which extends vertically through bore |48 of pillar |45 and projects through cap plate |41 in which it is rotatably guided. The projecting upper end of adjusting rod |5| is squared at |52 for receiving a handwheel or crank, not shown, by means of which rod |5| may be rotated to raise or lower cross-bar |50 for a purpose to be described. i.

The tool carriage 53 is splined upon pillar |45 by means of the four splines yor keys |54, but these keys do notfbear any lateral strains caused by the tendency of the entire carriage and pillar combination to rotate, because such lateral strains are absorbed by a lateral key |55, which slides vertically in guideways |56 in column 2|. The carriage |53 is provided with lateral slots into which the ends of the cross-bar |50 'lt, so that reeiprocating vertical movement of the cross-bar raises and lowers the tool carriage |53. The tool carriage is reciprocated by the action of crown cam |51 mounted on the under side of worm wheel 54 and shaped as illustrated in development in Fig. 9. 'I'his cam |51 is engaged by a follower roller |58 mounted on the end of lever |59 pivoted at |60 on the pedestal 22. The opposite end of lever |59 engages the lower end of push rod |49, so that carriage |53 is raised and lowered in accordance with the configuration of cam |51, the lowermost track |6| of which is rippled to provide small rapid reciprocating movements of the tool carriage for a purpose to be described later.

Four rods I 68 slidably extend downwardly from the upper flange of the column extension 2| through which they are adjustable lengthwise by nuts |69. Each of these rods is fitted with a collar |10, to which one end of tension spring 11| is connected. The other or lower end of each spring |1| is secured to a stud |12 secured in lower motor bracket |63. These springs counterbalance the greater portion of the weight of the heavy carriage |53 so that it may be moved readily by the cam |51 and manually by mechanism to be described.

The tool holders The carriage |53 is provided with six pairs of upper and lower brackets |62 and |63, respectively, which are connected by vertical guards |64, and which are spaced equi-angularly with six of the eight chucks on the turret 64. This leaves a gap between two pairs of brackets corresponding to the two remaining chucks below. Mounted between each pair of upper and lower brackets |62 and |63, and protected by the ,guards |64 is an electric motor 65 connected electrically to a source of power, not shown. The shaft |66 of each motor |65 extends downwardly through an opening in the corresponding lower bracket |63 and carries a grooved pulley |61, as shown in Figs. 1,2 and 13.

Journalled in brackets |13 formed integrally with carriage |53 `and located below the corresponding motors |65 and arranged eccentrically with respect to the shafts thereof are vertical pivot pins |14 on whichare mounted the tool holders |15, as is illustrated in Fig. 13. These tool holders each include upper and lower ears |16 which extend over the upper and lower ends of the corresponding bracket |13 and receive the corresponding ends of pivot pin |14. These ears |16 extend from the tool shaft housing |11, which is fitted with the elongated removable cap |18 and with a lateral web |19 covering the bracket |13. Journaled in suitable bearings in the shaft housing |11 of tool holder |15 is the tool shaft |80 which carries the grinding wheel |8| at its lower 'end and the grooved pulley |82 at its upper end.

The pulleys |61 and |82 lie in the same horizontal plane and are connected by a plurality of belts |83, by means of which the corresponding motor |65 drives the grinding wheel |81.

The lower ear |16 of each tool holder |15 is provided with an integral lug |84 through which is f threaded a set stud |85 locked in vadjusted posithe pin-and-slot arrangement shown in Figure 13,

so that the segments bear on bushing |89 and the gear |90 serves only to rotate them on the bushing. The cam |88 and gear |90 are housed within an enclosure comprising an overhanging apron |9| on the carriage |53 and a ring |92 which is seated in a groove in the surface of the carriage and closes the space between the latter and the lower rim of apron |9|. The actuating pins |81 are slidably mounted in bosses |93 formed on the outer surface of apron 9| and are urged into contact with the ring cam |88 by the pressure applied thereto by the tool holder springs |94, which are secured at one end to a pin |95 in the lugs|84 of the tool holders |15 and at their other ends to pins |96 on the cam apron |9|.

The angular position of cam |88 determines the radial position of each of the grinding wheels |8|, since movement of the cam |88 causes pins |81 to displace the corresponding tool carriers |15 about their pivots |14. The angular position of the cam |80 is adjusted by a pinion |91 mounted on the lower end of a vertical shaft |98 located Vwithin a shaft'housing |99 mounted on the front of the machine at the operators position or loading station. 'Ihe reduced lower end 200 of the shaft housing |99 is seated in a socket in the upper surface of the cam apron |9| and the .-.upper end thereof is secured to the carriage |53 by screws or the like, passing through lugs on the housing |99,yas illustrated in Figure 2.

The lower end of shaft |98 is suitably journaled in the shaft housing |99 and the upper end thereof is journaled in a sleeve 202 which in turn is journaled in shaft housing |99. The upper end of sleeve 202 is mush-roomed to form the in locking the latter against endwise movement and also secures worm wheel 201 thereto.

Journalled in housing 206 of lever 205 is a short shaft 2I0 having the worm 2|| meshing withv worm wheel 201 and a squared projecting end 2 I2 for the reception of a crank, or the like. The worm 2|| and wheel 201 are inherently locked with respect to each other so that shaft |98 is rotated only when lever 205 is oscillated or when worm 2| I is rotated.

The free end of lever 205 is provided with a roller 2 I3 which moves in a vertical groove or slot in relatively stationary block 2|4 as the carriage rises and falls in response to actuation by cam |51. The block 2 I 4 is secured to the end of a horizontal push-rodl 2|5 which is` slidably mounted in the upper end of column 2| and is prevented from rotating by a lateral extension 2I6 which is guided on a rod 2|1 secured in the column 2|. The lower surface of the extension 2I6 is fitted with a roller 2 I8 which is seated in and follows the groove of cam 2|9 mounted upon the upper end of cam shaft 55 and housed Within the column 2|. Cam 2|9 is so shaped that lever 205 is oscil- *Y lated as cam shaft 55 rotates, and, inasmuch as vertical shaft |98 is locked to lever 20,5 because of the worm and wheel combination 201, 2| the shaft |98 also oscillates. Because shaft |98 is connected to ring cam |88 through pinion |91 and ring gear |90, the cam |88 also oscillates to move actuating pins |81 outwardly and inwardly.

These movements of pins |81 cause tool'holders- |15 to oscillate about their pivots |14 so that their grinding wheels |8| are reciprocated in a horizontal plane. The several segments of the cam |88 may be of different shapes to provide corresponding movement of their tools. In this way, coarse grinders may be given a greater throw than the ne grinders, and the like.v

The cam 2|9 is so timed with respect to cam |51 that the respective movements of `the two cams alternate, i. e., when cam i 51 moves the carriage |53 upwardly to withdraw the grinding wheels |8| from the Work W, cam 2|9 holds lever 205 relatively stationary, and when the following action of cam 2|9 takes place to move the grinding wheels |8I laterally, cam |51 holds the carriage |53 stationary. Likewise, during the following downward movement of the carriage, which immediately follows the indexing of the turret 64, the lever 205 is stationary, and when cam 2|9 then moves the lever 205 to bring the grinding wheels |8I into engagement with the f work W, cam |51 holds the carriage stationary.

While the work is being ground, a small vertical reciprocation is imparted to the carriage |53, and consequently the grinding tools I8|, by the rippled track |6| of cam |51 to cause the grinding rings on the work to overlap and producea smoother surface. This square motion of the grinding wheels |8|, which isI secured by cams |51 and 2|9, is illustrated diagrammatically in Fig. 14, and the relation of the grinding wheels I8I to the work W is illustrated in Figs. 1 and 15, the work W being rotated in a counter-clockwise direction and the grinding wheel I8I in a clockwise direction, as seen from above, although these movements may be reversed if desired.

The grinding wheels |8I and the work W are flushed with water or other fluid during the grinding operation by nozzles 220, each controlled by suitable valves 22|, and connected by pipe ttings 222 to a manifold pipe 223 secured to inner surface of apron |20 and supplied by pipe 224 at the rear of the machine (Figs. 1 and 10).

The tool dressing devices Mounted in the path of each grinding wheel |8| during its withdrawing movement, is a dressing tool 226, which trues and dresses the grinding wheel after each grinding operation. 'I'his tool is a diamond chip or equivalent dressing element and, as illustrated in Fig. .11, is mounted in a holder 221 threaded into an arm 228 pivotally mounted on a bracket 229 secured to the apron |20 by a bolt 230. Arm 228 is locked in adjusted position on bracket 229 by pivot bolt 23| and the tool 226 may be more nely adjusted by screwing its holder 221 in or out of the arm 228. The head 232 for making this fine adjustment is graduated and cooperates with a pointer 233 xed on the arm 228 which enables the operator to obtain ilne, accurate adjustment for each of the dressing tools. A spring 234 holds the tool against loosening becauseof vibration, or the like. Accordingly, as the six grinding wheels |8| rise from the work W after the grinding operation,4 the constantly rotating wheels 98| I are trued and dressed by they corresponding dressing tools 226. Each tool is dressed according to its requirement, .although all tools are dressed simultaneously.

Inasmuch as each grinding operation and the subsequent dressing operation remove some of the surface of the grinding wheel, its diameter gradually decreases and so it must be advanced a corresponding amount to compensate for the reduced diameter in order that the subsequent and uniform. The mechanism for providing this compensation for wear and dressing losses on the grinding wheels includes a ratchet wheelr 235 secured on the outer end of the worm shaft 2m. Pivoted on worm shaft 2|0 is a pawl carrier 288 which carries at its lower end the pawl 231 engaging ratchet 235 and fitted with a lug 230 which is engaged by the free end of leaf spring 239 mounted on carrier 236. The pawl 231 has a knob 240, by which the operator may disable the compensating mechanism by pulling pawl from the ratchet 235, so that spring 239 snaps over lug 238 to hold the pawl 231 disengaged. A

, link 24| is pivoted upon the upper end of pawl carrier 236 and is pivoted at its opposite end to one arm 242 of bell crank 243 which in turn is pivoted on the lever 205. The other, or free end 244 of bell crank lever 243 is adapted to engage abutment 245 during the backward movement of lever 205, and since the bell crank 203 is carried by the lever 205, this action will result in oscillation of the bell crank 24,3. The resultant movement of link 24| to the right, as seen in Fig. 18, will cause pawl 231 to rotate ratchet 235, shaft 2|0, worm 2| I, worm wheel 201, shaft |98, pinion |91, ring gear |90 and cam |88 through a lirsV Y grinding operations of the tool Will be eiective/ small predetermined angle and since this rotation l is superimposed upon the oscillating movement of cam |88, the result is a permanent advance of the corresponding grinding wheel a distance equal tothe decrease in its radius caused by the wear and dress thereof. This compensating adjustment is timed to take place during the upper horizontal course of the grinding wheel, as seen in Figure 14, so that the adjustment takes place when the grinding wheel |6| is Withdrawn from the work W.

In order to restore the paw] 231 for the next operation, a tension spring 246 is connected between the bell crank 242 and the lever 205, which,

when the lever 205 moves forward to advance the wheel ll against the work, pulls link 24| to the left, as seen in Figure 18, to return pawl 231 to its starting point, the latter clicking over the teeth of ratchet 235 to assume its new position. A stop screw 241 for the bell crank 242 limits this restoring action of the spring 246 and is adjustable.

The compensating movement of each grinding wheel takes place during each square movement thereof and is continued until the grinding face of a wheel is Worn and dressed down to a point where it is no longer eiective. This condition of a wheel is definitely known to take place after a predetermined number of compensating movements of the mechanism and after that condition is reached it is desirable to stop further compensating movements so that the worn tool will not injure the work or other part. Since the number of compensating movements is known, and since the rotation of worm wheel 201 by worm 2li is proportional to these movements, the worm may be employed to determine the limit of these movements. To this end the worm 201 is tted with a crown cam 248 which gradually approaches a detent 249 located in its path and slidable vertically in an opening inthe housing 206. This detent normally holds latch 250 retracted, this latch having a hook 25| which ts over the edge of an eye in detent 249 through which the latch 250 passes. A spring 252 urges the latch to the left, as seen in Figure 19. The latch 250 slidable in a boss 253 in the housing 206 and its free end is notched for cooperation with the edge of pawl carrier 236 of the compensating mechanism when the latch is released. When the worm wheel 201 has rotated the aforementioned predetermined number of stops, detent 240 rides upon cam 248 to release the latch 250, which is thereupon urged to the left as seen in Figure 19, so that its end steps over the edge of link 24| upon its compensating stroke so that the end 244 of bell crank 243 remains retracted Vand will not be advanced by the subsequent stroke of the. lever 205. Accordingly, the compensating mechanism is disabled automatically and will not again function until restored by the operator after he has replaced the yworn grinding wheel with a new one. In order to restore the disabled compensating mechanism, the operator ts a crank or handwheel on the squared end 212 of worm shaft 2|0 and rotates the latter in a direction opposite to that in vwhich it was moved by the pawl 231 until the mechanism is rel stored to its initial position. Then the operator disengages latch 250 from pawl carrier 236 and catches its hook end within the eye of detent 249 and the mechanism is ready for its next operation.

Manual tool carriage elevati-a stored without changing its adjustment with respect to the Work. The mechanism for raising and lowering the carriage is located at the front of the machine on shaft housing |99. It is enclosed in a casing 254 formed integrally with the shaft housing |99, as is illustrated in Figs. 2, 12 and 22. Extending through casing 254 and keyed against movement therein is a vertical rod 255 which is provided with a threaded lower end 256, and which extends through a lug 251 on column extension and is adjustable lengthwise therethrough by means of nuts 258. Engaging upper thrust bearing 259 and threaded in the lower end 256 of rod 255 within the casing 254 is a bevel pinion 260 with which meshes a second bevel pinion 26| xed in the inner end of horizontal shaft 262, whose projecting outer end 263 is squared for the reception of a crank or handwheel, not shown.

It will be seen that by rotating shaft 262 by means oi a crank'or handwheel, the bevel pinion 26| travels up or down rod 255 to raise or lower the entire carriage |53 for the purposes mentioned. `Manipulation of this mechanism is easy and not laborious, despite the weight of the carriage because the counter-balancing tension springs |1| relieve much of the weight of the carriage. It will be seen that the elevation of the carriage in this way simply lifts the end of adjusting rod out of contact with push-rod 49 which is accordingly not disturbed, and the setting of the carriage reciprocating cam |51 is also notdisturbed in any way. Conversely, when the carriage is again lowered, adjusting rod |5| simply again engages the upper end of push rod |49 and the carriage is restored exactly to its initial position.

Likewise, thesetting of the carriage traversing cam 2|9 is not disturbed, as the roller 2| 3 on the end of lever 205 simply slides up and down in its slot in block 2|4 as the carriage is raised and lowered. Thus, one or more tools may be removed and replaced and other changes may be made with facility and ease without disturbing the adjustment of any oi the other parts of the machine.

In addition to elevating the tool carriage bodily, its vertical position with respect to the turret may be adjusted at will to change the relation between the tools and the work, such as when it is desired to begin the cut at a higher or lower point on the surface of the work. This adjustment is performed by adjusting rod |5| which raises or lowers the cross bar |50 which supports the tool carriage on the adjusting rod |5|. Accordingly, by rotating adjusting rod |5| in one direction, the tool carriage may be lowered so that the grinding wheels 8| extend further into the work W, and vice versa. It will be seen that this adjustment, which should be made when the tools are out of contact with the work, does not affect the position of the tool holder traversing mechanism nor disturb the contact between the tool carriage and its reciprocating cam |51.

Summary of operation Prior to starting the machine, the operator elevates the entire tool carriage by means of a -`crank placed on the squared end 263 of shaft ends of the tool holder spindles |80. Each grindy ing wheel is driven by its individual motor in a clockwise direction, as seen from above, i. e., opposite to the direction of rotation of the work (Fig. 15).

If the surface of a rough casting, forging, or the like, is to be ground down to a fine finish or lap, the rst grinding wheel or wheels of theseries are coarse grinding or roughing wheels and the coarseness or grinding properties of the wheels of the series are graded down to the last wheel, which may be an extremely fine grinding wheel, or even a lapping or bufiing tool, depending upon the nish required. In the particular machine illustrated, six tooling stations are provided requiring six grinding wheels as compared to the eight work-holding chucks, two of which are located at the loading station between each indexing movement of the turret for removal of the finished work and reloading of the emptied chucks. No tool holders are provided at the loading station. Accordingly, the i'lrst tool I8| may be a coarse roughing Wheel, the second tool may be a less coarse roughingl tool for dressing the work down to approximately theproper dimension, the third and fourth wheels may perform graded finer grinding, while the' fifth.A and sixth 4wheels may provide the graded finishing grinding required for the particular work.

Because of the differing grinding functions required of the several grinding wheels and the gradual recession of the surface of the work being ground, the relative starting positions and feeds of the several wheels should differ appropriately in order to secure eiiicient, rapid and accurate grinding. Also, the coarse wheels wear down more rapidly than the ne wheels and this must be taken into consideration in order that the wheels will grind uniformly on the successive pieces of work. All of these factors are taken into consideration in the present machine. For

example, by adjusting the set studs |85 (Fig. 13) \of the several tool holders |15, the starting position of each tool may be adjusted. Accordingly, the set stud of the first coarse tool is'adjusted to cut deeper in to the work than the succeeding tools and the set stud of the sixth or last tool is adjusted so that it just engages the surface of the work and provides the fine finish or lap. f

The progressively decreasing feed of the successive tools is provided by the increased pitch of the corresponding segment of ring cam, so that the throw of the first or roughing tool is` greater than the throw of the second tools and so on until the sixth and last tool has a. very slight throw commensurate with the fine or lapping action required thereof. The varying pitches of the segments of the cam |58 also compensate for thevarying wear of the corresponding wheels which takes place in proportion to the coarseness of the wheels.

Having selected and attached the wheels of the proper dimensions and grades the operator again lowers the tool carriage |53 by manipulating the crank on shaft 252 until the lower end of adjusting rod |5| rests upon the upper end of push rod |49, so thatthe unbalanced weight of the tool carriage |53 is supported by the cam |51 (Fig. 9), the major proportion of the carriage weight being counterbalanced by the tension springs IH.

With the tool carriage at its lowermost position, as determined by the low track |6| of the cam |51, the operatorrotates adjusting rod |5|,

by means oi'. a crank placed on its squared end |52, until the tools IBI are located at their lowermost cutting position with respect'to the surface of the work W, which is used as a gauge for this purpose. This adjustment of the rod |5| causes it to screw into or out of the cross bar |50 which supports the tool carriage |53 so that the vertical position of the carriage is adjusted.

The dressing tools 226 are individually adjustable by means of dials 232 so that they project inwardly a very slight distance beyond the vertical plane of the surface of the work W after it is ground so as to cut and accordingly true and dress the corresponding tool during its vertical retracting movement from the work which it has just nished grinding. Accordingly, although all of the tools |8| are dressed simultaneously, each tool is dressed individually according to the nature of its surfaceafter each grinding operation.

yAfter themachine has been prepared for opr eration, the operator starts it by throwing handle |43 to the right, as seen in Fig. 2. This rotates rod 6| so that its downwardly turned crank 52 shifts rod l0 to the left, as seen in Fig. 6, to engage main drive clutch 31. The clutch 8| couples worm driven Wheel 50 through ratchet 5|, 52 to shaft 36, which, through worm 53 and worm wheel 5t drives cam shaft 55, which controls the operation of the several parts of the machine.

Having started the machine, the operator loads the work-holding chucks as they are advanced one by one to the loading stations. IIn order to reach the'chucks for loading the operator depresses treadle |23 to retract work holding fingers H1 from their normal position over the workholding chucks, located at the loading station. Two chucks are in position at the loading station at a time, although advanced to this position one at a time by each indexing movement of the turret. As each chuck reaches the loading station, it and the chuck preceding it are automatically opened by pins |05 aligned with the chuck spindles 3Q and elevated by cam H3. Also, as the chucks are broughtto the loading station, their rotation is arrested by the automatic disengagement of their clutches 89, e@ by cam |05, which is engaged by the rollers |04 of the clutch release levers |02.

With the fingers retracted from the stationary open chucks at the loading station, the operator may insert the pieces of work W therein, placing them so that the centering pins 82 of Athe chuckflt into the corresponding flange holesn of the work, as indicated in Figures 'I and 15, still assuming that the work is an automobile hub,

although the chucks may be adapted to hold other pieces of work in a manner readily understood. The operator then releases treadle |23 and spring |25 moves fingers over the pieces of work Wk which are engaged by the collet ngers 81 of the chucks when the latter/are released by disengagement of their spindles 86 by pins |06, which are withdrawn by cam llt immediately before the next indexing movement of turret 84.

The dwell periodof the turret is of sufcient duration to give the operator ample time to remove inished pieces of work -from the chucks and replace them with new work before the turret is indexed a step and the leading chuck advanced so that its clutch release roller |04 rides off of stationary cam |05 to permit reengagement of, the clutch 39, 00 byl spring 99. This chuck,

as well asfthose at the working stations. is rotated by ring gear 92 which is driven by bevel gear 95 of drive shaft 90. Each chuck is rotated in a counter-clockwise direction, as seen from above, which is opposite to the direction of vrotation of the tools.

The turret 64 is indexed step-by-step by periodic engagement between rollers 66 on cam disc 58 with one of the spaced lugs 81 on the turret ring 68. During the period that the rollers 66 are .in engagement with a lug 61, the speed of `cam shaft 55, on which the cam dise 58 is mounted, is increased automatically so that the turret 64 is indexed rapidly. This speed change is provided by the variable speed mechanism which is illustrated especially in Figs. 4, 5 and 6 and is controlled by cam 59' von the cam disc 58. As the indexing movement begins, cam 59' actuates bell crank 60 to shift rod 34 to the left and engage high speed clutch 3|. 'I'his clutch, through gears 30 and 35 and clutch 31 drives shaft 36 faster than it is normally driven by worm 49, and since cam shaft 55 is driven by shaft 36 through worm 53 and worm wheel 54, the cam shaft 55 is drivenat greater speed and a fast indexing movement results. When cam 59' releases bell crank 60, cam 59 disengages high speed clutch 3| and the normal relatively slow drive of the cam shaft 55 results. Accordingly, the major part of the time of operation of the machine is working time, since little time is occupied in indexing and feeding the tools to and from the work. Between indexing movements of the turret, the latter is locked by pin 69 actuated by cam.14.

Assuming that the machine starts with tool carriage |53 in its uppermost position and the tool holders |15 in their inner or retracted positions, the tools |8| are located with respect to the corresponding pieces of work as is indicated by the dot-and-dash outline of one of the tools |8| in the upper left-hand corner of Fig. 14, i. e., directly above the hole in the work W but retracted out of the vertical plane of the surface to be ground.

Further rotation of tool carriage reciprocating cam |51 results in the relatively slow descent of follower |58 to the lower track |6| of the cam so that the tool carriage is lowered to its lowermost position and the tools |8| are introduced into the plane of the work and Within the holes of the corresponding pieces of work, although not in contact therewith. This position of the tool is indicated by the dot-and-dash outline of the tool in the lower left-hand corner of Fig. 14.

As the tools reach the plane of theY work in position for cooperation therewith, their vertical movement is arrested, except for a small reciprocation to be described, and the lateral feed of the tools in the plane of the work into cooperative relation with the surfaces to be ground takes place. This lateral feed of the tools is performed by traversing the tool holders |15 horizontally relatively to the tool carriage |53 and the turret 64. This traversing movement of the tool holders |15 is provided by rotation of ring cam |88, whose individual segments advance the correspending actuating pins |81 tov Swing the tool holders |15 about their pivots |14 through an angle determined by the contour of the cam segment, so that the tools |8| are advanced in the plane of the work and engage the surface to be ground, the relative position of the tools being indicated by the full line outline in Fig. 14. This feed of the tools continues after the tools engage the work until the tools cut to the depth determined by the throws of the corresponding segments of cam |88.

The rotation of ring cam |88 to provide this feeding movement of the tools |8| in the plane of the work is performed by the radially outward throw of push rod 2|5 by cam 2 |9 mounted on the upper end of cam shaft 55 (Figsl, 2 and 3). The push rod 2|5 actuates lever 205, which through locked worm 2|| and worm wheel 201 rotates vertical shaft |98 having pinion |91 at its lower end, which rotates ring gear in a clockwise direction as seen from above. This ring gear carries the segmental cam |88, which accordingly traverses the tool holders in the manner described.

While the tools |8| are in grinding engagement with the work W, the rippled lower track |6| of cam |51 (Fig. 9) rapidly reciprocates the tool carriage so that tools are wiped across the surface being ground to cause overlapping of the grinding rings made thereon by the abrasive particles of the tools, whereby a smoother ground surface results.

During the dwell period of tool traversing ram 2|9, which follows the tool feeding operation thereof, the follower |58 rises on the steep incline of cam |51 (Fig. 9) and the tool carriage is rapidly elevated, so that each tool lies in the relative position indicated by the dot-and-dash outline in the upper right-hand corner of Fig. 14, with its grinding surface in the vertical plane of the surface just ground thereby. During this upward movement of the tool carriage the surfaces of the rotating tools are raked by the dressing devices 226 as indicated in Figs. 10 and 11, so that each tool is trued and dressed individually according to its requirements, although all six of the tools are dressed simultaneously.

During the dwell period of cam |51 when the tool carriage remains in its uppermost position, cam 2| 9 again comes into action to withdraw push rod 2|5 and swing lever 205 backwardly as seen in Fig. 3. This causes counterclockwise rotation of ring cam |88 and the resultant retraction of tool holders |15 by their springs |94, so that the tools are traversed laterally inwardly, as seen in Fig. 14. Just prior to the end of the retracting movement of lever 205, the free end of bell crank lever 243 engages and, is actuated by abutment 245, and, by means of link 24| actuates l pawl 231 which rotates ratchet wheel 235, worm 2| worm wheel 201, shaft |98, attached pinion |91, and ring gear |90 through a small angle. It is noted that this resulting small movement of cam |88 is ysuperimposed upon and is opposite to the major movement of the cam |88 produced by the rearward movement of lever 205 by cam 2|9. This reduces the net retractive movement of the tools |8| an amount equal to the reduction in radius of the tools caused by the Wearing and dressing thereof, so that during the subsequent feeding movement of the tools to the work they are advanced to the same relative position with respect to the next pieces of Work as they occupied with respect to the preceding pieces of Work during the tooling operation. In other words, the reduction in radius of the tool is automatically compensated for, even to the extent of compensating for the varying degree of wear of the several tools, since the corresponding segments of cam |88 have varying pitches. lFor example, the pitch of the cam segment of the first or roughing Wheel is greater than that of the remaining segments because of the deeper cutting required of it. The roughing wheels also wear compensation for wear is required.. This greater compensation naturally results because of the.

increased pitch of the cam segment of the roughing wheel. Accordingly the Wear of each Wheel is compensated for toa degree commensurate to the wear thereof.

As the tools gradually wear down to the core or to a point where they are no longer effective, the compensating mechanism is disabled by cam 248 on worm Wheel 201 of the compensating mechanism (Figs. 17, 18 and 19). This cam is stepped around to the point Where a tool wears down and releases latch 250 which is projected into the path of pawl carrier 236 to prevent further compensating movement thereof. Since vsome wheels wear down sooner than others, only those wheels need to be replaced at a time. The dial on shaft |98 at the loading station (Fig. 2) indicates the condition or position of the compensating mechanism at all times.

During the retracting and compensating movements of the tools in the horizontal plane above the plane of the work, the indexing movement of the turret 64 takes place, whereby each piece of work is advanced a step in alignment with the tool which is to perform the next tooling operation, with the exception of the piece of work which was acted upon by the sixth or finishing tool and this piece of work is advanced to the unloading station for removal and replacement by a new piece of work. A s aforementioned this indexing movement is rapid, being provided by the high speed gearing of the main driving' mechanism.

Ifthe operator fails to depress treadle |23 rato to removing the finished work, the saxal 34 (rFYigs. 1 and 2) actuates levers |29 and |21 and detent |36 engages abutment |38 to drop hook |42 into engagement with pin |43 of control handle |43. The continued movement `of lever |21 by cam |34 causes hook |42 to pull handle |43 to the left, as seen in Fig. 2, so as to disengage main drive clutch 31 (Fig. 6,) and stop the machine. This prevents regrinding of the nished piece of work. However, if the'operator depresses treadle |23 at the proper time, lever |21 and detent |36 are lowered, as illustrated in Fig. 21, so that upon movement of lever |21 to the right by cam |34, detent clears abutment |38, while detent |31 engages abutment |39 to lift hook |42 clear of pin |43', so that the handle |43 is not actuated. This safety arrangement accordingly feels whether or not the operator has acted to remove the finished work, and if he has not, the mechanism responds by stopping the machine.

This safety arrangement also has another safety function. If the operator is in the act of replacing work in an open chuck at the loading station, holding treadle |23 depressed at the time in order to Vhold ngers ||1 out of the way, but is unable to complete the loading operation before the chuck closes, the latch |4| will also engage pin |43', so that the subsequent feeler action of cam |34 will stop the machine before the partially loaded chuck is carried to a grinding station with consequent injury to the work and possible injury to the associated machine parts.

The foregoing describes the single indexing movement of the turret when each successive tool engages each successive piece of Work. Under certain conditions it is desirable to double index, i. e., present the work to alternate tools for perfaster than the nner wheels, so that a greater forming different grinding operations, such as inside grinding at alternate stations and outside grinding at the remaining stations, grinding of different aligned surfaces either inside or outside of the work, grinding alternate pieces 'of work in the reversed position, -and the like. Also if a small amount of stock is to be removed the double chucking arrangement would increase production. In any case, two pieces of work are loaded at a. time at the loading station, and there would be three grinding stations for each piece instead of six, as in the case of the single indexing movement described. As aforementioned, the machine may be converted quickly and simply into double indexing by substituting the four-roller cam disc illustrated in Figure 4A for the two-roller disc 58 illustrated in Figure 4, the four rollers 66' securing the double angle movement and cam 59' holding locking pin 69 out of engagement with alternate notches 70 to permit the double index.

It will be seen that in the machine of the present invention the individual pieces of work are treated at each station to the particular cutting action which is necessary to secure the desired result most rapidly, elciently and economically. This involves variable feeding of the several tools,

spending upon their abrasive properties, the nature of the cut required of them and the condition of the surface of the work being tooled. Each of these factors is accommodated by the independent feed and adjustability of the individual tools, which are not dependent upon the movements of massive machine parts and accordingly can be as delicate and accurate as the nature of the work requires.

Among the numerous novel features of the machina especial importance is attached to the straight line out of coacticn with the pieces of work just ground thereby, carries their grinding surfaces into coaction with and past the cutting surfaces of the dressing tools, so that extreme accuracy in the dressing of the tools is attainable and such extreme accuracy is essential to the successful operation of a machine for such uses as those for which the present machine is particularly adapted.

Also, while the grinding wheels are all mounted upon the same tool carriage and are moved axially thereby, they are all capable of different' amounts of movement in a substantially radial direction and the movement of each is independent of the ymovement of all the other tools. Although the several grinding tools are moved in a substantially radial direction each independently of all `the others, the machine of this invention employs a single compensating means governing all of them to compensate for the wear on the grinders incident to the grinding operation and for the dressing of the grinding tools. The use of a single compensating means for all of the tools rather than individual compensating means for each of the several grinding tools is made possible because of the individual actuating means for positioning the several grinding tools, i. e., the individual segments of the ring cam |88. It is by reason o the use of these several individual actuating means for positioning the tools each independently of all the others that unnecessary excess wear of some of the tools is avoided, the maximum service of each'of the grinders is attained, and the substitution of a single new grinder at any time is possible.

The use of individual motors for the several tools permits adjustment of the speed of rotation of the tools commensurate with the work required of them, and this adjustment is made either by regulating the speed of the motors by well known means or by employing driving pulleys` of thc proper diameters.

Although the machine has been illustrated and described as performing inside grinding, it will perform outside grinding with equal facility and the various movements of the machine may be employed for performing tooling operations other than grinding.`

I claim:

l. In a machine of the class described, the combination of a work holding member having a plurality of work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged in circular series, means for moving the members relatively axially to place the tools and the work into position for cooperative relation, and means for simultaneously moving the tool holders laterally with respect to said tool holding member and independently of the movement of the members to engage the tools with the Work.

2. In a machine of the class described, the combination of a work holding member having a plu rality of work holders arranged in circular series, a toolholding member having a plurality of tool holders arranged in circular series, means for intermittently moving the members relatively angularly to place the tools and the work successively into positionA for cooperative relation, and

means for simultaneously moving the tool holders laterally with respect to said tool holding member and independently of the movement of the members to engage the tools with the work.

3. In a machine of the cla-ss described, the combination of a work holding member having a plurality of Work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged in circular series, means for intermittently moving the members relatively angularly to successively place the work and tools in substantial alignment, means for moving said members relatively axially to place the tools and the work into position for cooperative relation, and means for simultaneously moving the tool holders laterally with respect to said tool holding member and independently of the. movement of the members to engage the tools with the work.

4. In a machine of the class described, the combination of a work holding member having a plurality of work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged "in, circular series, means for moving the members relatively axially to place the tools and work into position for working engagement, means for simultaneously moving the tool holders laterally with respect to said tool holding member and independently of the movement of the members to engage the tools with the work, and means for relatively reciprocating the tools and Work While in engagement independently ofthe movement of the tools and work into and out of engagement.

5. In a machine of the class described, the combination ofy a work holding member having a plurality of work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged in circular series, means for simultaneously moving the tool holders laterally with respect to said tool holding member and independently of the movement of the members to engage the tools with the Work, and means for relatively reciprocating the members while the Work and tools are in engagement independently of the movement of the tools and work into and -out of engagement.

6. In a machine of the class described, the combination of a work holding member having a plurality of work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged in circular series, means for moving said members relatively to place the tools and the Work into position for cooperative relation, means for simultaneously moving the tool holders relatively to the work holders independently of the said relative movement of the members, and means responsive to the movement of the tool holders for advancing the latter after lach operation to compensate for the wear of the ols.

'7. In a machine of the class described, the combination of a work holding member having a plurality of Work holders arranged in circular sey ries, a tool holding member having a plurality of tool holders arranged in circular series, means for moving the tool holders relative to the Work holders for feeding the tools into engagement with the work, means for relatively moving the tool holders and the work holders axially out of engagement, a relatively stationary dressing device in the path of the said relative axial movement of each tool for dressing the surface thereof, and mechanism responsive to the said feeding movement of the tool holders for adjusting the rslt means to compensate for the dressing of the too s.

8. In a machine of the class described, the combination of a work holding member having a plurality of Work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged in circular series, means for/moving the members relatively axially to place the tools and work into position for cooperative relation, means for traversing the tool holders laterally with respect to the members and independently of movement of said members to engage the tools and the work, and means responsive to the traversing movement of the tool holders for simultaneously varying the relation between the tools and the work to compensate for the wear of the tools.

9. In a machine of the class described, the combination of a work holding member having a plurality of work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged in circularseries, means for relatively moving the members axially to place the tools and work into and out of position for cooperative relation, means for relatively moving the members step-by-stcp to present the tools and work successively for the said cooperative relation, and means alternating with the relative axial movements of the members for advancing and retracting the tool holders substantially radially with respect to the members and independently of the movement thereof, whereby the tools describe a substantially rectangular path with respect to the corresponding pieces of work. 10. In a machine -of the class described, the combination of a work holding member having a plurality of work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged in circular series, means for relatively moving the tools and work into cooperative relation, means for relatively moving the members step-by-step to place the successive tools and work in position for the said cooperative relation, means timed with the relative step-bystep movement of the members for successively opening the work holders at an unloading station, means preventing removal of the work from the work holders, manual means at the unloading station for disabling said last named means, and means responsive to failure of operation of said manual means for disabling at least the stepby-step means to prevent nished work from being carried past the unloading station.

11. In a machine of the class described, the combination of a work holdingmember having a plurality of work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged in circular series, common means for simultaneously feeding the several tools into cooperative relation with the corresponding pieces of work, and variable devices in the feeding means for adjusting the position of at least part of the tools relatively to the corresponding pieces of work and the other tools.

12. In a machine of the class described, the combination of a work holding member having a plurality of work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged in circular series, common means for simultaneously feeding the several tools into cooperative relation with the corresponding pieces of work, and devices in the feeding means for varying the feed of the individual tools relatively to the corresponding pieces of work and the other tools.

13. In a machine of the class described, the combination of a work holding member having a plurality of work holders arranged in circular series, a tool holding member having a plurality of tool holders arranged in circular series, means for feeding the several tools into cooperative relation with the corresponding pieces of work, means for relatively moving the members step-bystep to present the tools and work successively to each other, means for independently adjusting the tools with respect to each other to provide different tool action on the successive pieces of work, and common means for feeding the tools to and from the work.

14. In a machine of the class described, the combination of a work-holding member having a plurality of work holders, a tool holding member having a plurality of tool holders corresponding to at least part of the Work holders, means for simultaneously relatively moving the work holdto the other tools and prior to the said cooperative relation between them.

l5. In a machine of the class described, the combination of a turret having a plurality of work holders arranged in circular series, a tool carriage aligned axially with the turret, a plurality of tool holders mounted on the tool carriage in circular series tand traversible substantially radially with respect thereto, means for intermittently indexing the turret to substantially align successive tools and pieces of workmeans for reciprocating the tool carriage for advancing and withdrawing the tools into and out of the plane of the work, and means for traversing the tool holder to feed the tools to the work when in the plane of 'thtlatter and for retracting the tool holders laterally relatively to the tool carriage when withdrawn from the plane of the work by the tool carriage.

16; In a machine of the class described, thecombination of a turret having a plurality of work holders arranged in circular series, a tool carriagealigned axially with the turret, a plurality of tool holders mounted on the tool carriage in circular series and traversible substantially radially with respect thereto, means for intermittently indexing the turret to substantially align successive tools and pieces of work, means for reciprocating the tool carriage for advancing and withdrawing the tools into and out of the plane of the work, and a cam for traversing the tool holders inwardly and outwardly in a substantially radial direction relatively to the tool carriage for alternately feeding the tools into engagement with the work when in the plane thereof and retracting the tools when out of the plane of the work.

17. In a machine of the class described, the combination of a lturret having a plurality of Work holders arranged in circular series, a tool carriage aligned axially with the turret, a plurality of tool holders mounted on the tool carriage in circular series and traversible substantially radially with respect thereto, means for intermittently indexing the turret to substantially align successive tools and pieces of work, means for reciprocating the tool carriage foi` advancing and withdrawing the tools into and out of the plane of the work, a cam-for traversing the tool holders inwardly and outwardly in a substantially radial direction relatively to the tool carriage for alternately feeding the tools into engagement with/the work when in the plane thereof and retracting the tools when out of the plan-e of the work, and means for adjusting each tool holder relatively to the cam.-

18. In a machine of the class described, the combination of a turret having a plurality of work holders arranged in circular series, a tool carriage aligned axially with the turret, a plurality of tool holders mounted on the tool carriage in circular series and traversible substantially radially with` respect thereto, means for intermittently indexing the turret to substantially align successive tools and pieces of work, means for reciprocating the tool carriage for advancing and withdrawing the tools into and out of the plane of the work, a cam for traversing the tool holders inwardly and outwardly in a substantially radial direction relatively to the tool carriage for alternately feeding the tools into engagement with the work when in the plane thereof and retracting the tools when out of the plane of the work, and means responsive to each traversing movement of the tool holders in one direction for adjusting the cam relatively to the tool holders to compensate for the wear of the tools.l

19. In a machine of the class described, the F combination of a turret having a plurality of work holders arranged in circular series, a tool carriage aligned axially with the turret, a plurality of tool holders mounted on the tool carriage in circular series and traversible substantially radially with respect thereto, means for intermittently indexing the turret to substantially align successive tools and pieces of work, means for reciprocating the tool carriage for advancing and withdrawing the tools into and out of the plane of the work, and anv oscillating cam having a segment for each tool holder of a contour appropriate for providing the requisite movement of the corresponding tool.

20. In a machine of the class described, the combination of a turret having a plurality of work holders arranged in circular series, a tool carriage aligned axially with the turret, a plurality of tool holders mounted on the tool carriage in circular series and traversible subst-antially radially with respect thereto, means for intermittently indexing the turret to substantially align successive tools and pieces of Work, means for reciprocating the tool carriage for advancing and withdr-awing the tools into and out of the plane of the work, means for traversing the tool holders relatively to the tool carriage to feed the tools into cooperative relation with the corresponding pieces of work, means responsive to the traversing movement of the tool holders for advancing them relatively to the work to compensate for wear of the tools, and stop mech-anism for disabling the compensating means upon wearing down of at least one of the tools.

2l. In a machine of the class described, the combination of a turret having a plurality of work holders arranged in circular series, a tool carriage aligned axially with the turret, a plurality of tool holders mounted on the tool carriage in circular series and traversible substantially radially with respect thereto, means for intermittently indexing the turret to substantially align successive tools and pieces of work, means for reciprocating the tool carriage for advancing and withdrawing the tools into and out of the plane of the work, means for rotating the work holders, a normally engaged clutch in the rotating means of each work holder, and means responsive to the indexing movements of the turret for disengaging the clutch of certain of the work holders to stop the rotation thereof during the corresponding indexing movement of the turret.

22. In a machine of the class described, the combination or" a turret having a plurality of work holders arranged in circular series, a tool carriage aligned axially of the turret, a plurality of tool holders pivoted on the tool carriage in circular series and swingable about their pivots relatively to the tool carriage, an individual motor for each tool holder, a cam for swinging the tool holders to feed the tools into and out of cooperative relation with the Work, means for reciprocating the tool carriage axially of the turret to advance and withdraw the tools into and out ,of the plane of the work and means for intermittently indexing the turret when the tools are withdrawn from the plane of the work for presenting successive pieces of work to the tools.

23. In a machine of the class described, the combination of a turret having a plurality of work holders arranged in circular series, a tool carriage aligned axially with the turret, a plurality of tool holders mounted on the tool carriagel in circular series and traversible substantially radially with respect thereto, means for intermittently index' ing the turret to substantially align successive tools and pieces of work, means for reciprocating the tool carriage for advancing and withdrawing the tools into and out of the plane of the Work,

and means for withdrawing the tool carriage independently of the reciprocating means thereof and without disturbing the latter.

24. In a machine of the class described, the combination of a turret having a plurality of work holders arranged in circular series, a tool carriage aligned axially with the turret, a plurality of tool A holders mounted on the tool carriage in circular series and traversible substantially radially with respect thereto, means for intermittently indexing the turret to substantially align successive tools and pieces of work, means for reciprocating the tool carriage for advancing and withdrawing the tools into and out of the plane of the Work, and means for adjusting the elevation of the tool carriage independently of the reciprocating means to change the axial relationship betweenthe tool carriage andthe turret.

25. In a grinding machine, the combination of a turret rotatable step-by-step,a plurality of rotatable work-holders mounted in circular series .upon the turret, a tool carriage mounted in axial alignment With`the turret and movable axially with respect thereto, a plurality of tool holders mounted on the tool carriage in circular series, means for rotating the tool holders, grinding tools mounted uponA the tool holders, means for simultaneously moving said grinding tools laterally relative to the tool carriage independently of they movement of the carriage to engage the tools with the work, and a plurality of dressing tools each corresponding to' one of the grinding tools and each mounted with its cutting edge in alignment with the surface ground and in position to be engaged by the grindingsurface of the grinding tool as the grinding tool is moved out of coaction with the work being operated upon by the axial movement of the tool carriage relatively to the turret.

26. In a grinding machine, the combination of a turret, a plurality of work holders arranged in circular series thereon, means for rotating the Work holders, means for indexing the turret/a tool carriage mounted for movement axially with respect to the turret, a plurality of tool holders mounted on the tool carriage, means for rotating the tool holders, grinding tools mounted on the tool holders, means for moving the grinding tool holders substantially radially in alternation with axial movements of the tool carriage relatively to the turret, whereby each of the grinding tools is caused to traverse a substantially rectangular path, a plurality of dressing tools each corresponding to one of the grinding tools and each mounted with its cutting edge in alignment with the aligned surfaces of the grinding tool and thesurface of the work` ground thereby in position to be engaged by the corresponding grinding tool during the axial movement of the tool carriage.

27. ,In a grinding machine, the combination of a turret, a plurality of Work holders arranged in circular series thereon, means for rotating the Work holders, means for indexing the turret, a tool carriage mounted for movement axially with respect to the turret, a plurality' of tool holders mounted on the tool carriage, means for rotating the tool holders, grinding tools mounted on the tool holders, means for moving the grinding tool holders substantially radially relatively to the .tool carriage in alternation with axial movements of the tool carriage relatively to the turret, whereby each of the grinding tools is caused to traverse a substantially rectangular path, the

said means for eiecting movement of the toolv 

